Attempt to fix bad registry errors, fixes #432 and #433

common/src/main/java/org/mvndaemon/mvnd/common/DaemonRegistry.java

@@ -16,9 +16,9 @@
 
 package org.mvndaemon.mvnd.common;
 
-import java.io.File;
 import java.io.IOException;
 import java.lang.management.ManagementFactory;
+import java.nio.ByteBuffer;
 import java.nio.MappedByteBuffer;
 import java.nio.channels.FileChannel;
 import java.nio.channels.FileLock;
@@ -139,6 +139,10 @@ public void storeStopEvent(final DaemonStopEvent stopEvent) {
 
     public List<DaemonStopEvent> getStopEvents() {
         read();
+        return doGetDaemonStopEvents();
+    }
+
+    protected List<DaemonStopEvent> doGetDaemonStopEvents() {
         return new ArrayList<>(stopEvents);
     }
 
@@ -242,12 +246,28 @@ private void doUpdate(Runnable updater) {
                     return;
                 } catch (IOException e) {
                     throw new RuntimeException("Could not lock offset 0 of " + registryFile);
+                } catch (IllegalStateException | ArrayIndexOutOfBoundsException e) {
+                    String absPath = registryFile.toAbsolutePath().normalize().toString();
+                    LOGGER.warn("Invalid daemon registry info, " +
+                            "trying to recover from this issue. " +
+                            "If you keep getting this warning, " +
+                            "try deleting the `registry.bin` file at [" + absPath + "]", e);
+                    this.reset();
+                    return;
                 }
             }
             throw new RuntimeException("Could not lock " + registryFile + " within " + LOCK_TIMEOUT_MS + " ms");
         }
     }
 
+    private void reset() {
+        infosMap.clear();
+        stopEvents.clear();
+        BufferCaster.cast(buffer).clear();
+        buffer.putInt(0); // reset daemon count
+        buffer.putInt(0); // reset stop event count
+    }
+
     private static final int PROCESS_ID = getProcessId0();
 
     private static int getProcessId0() {
@@ -271,7 +291,7 @@ private static int getProcessId0() {
         }
     }
 
-    private String readString() {
+    protected String readString() {
         int sz = buffer.getShort();
         if (sz == -1) {
             return null;
@@ -284,16 +304,26 @@ private String readString() {
         return new String(buf, StandardCharsets.UTF_8);
     }
 
-    private void writeString(String str) {
+    protected void writeString(String str) {
         if (str == null) {
             buffer.putShort((short) -1);
-        } else if (str.length() > 1024) {
-            throw new IllegalStateException("String too long: " + str);
-        } else {
-            byte[] buf = str.getBytes(StandardCharsets.UTF_8);
-            buffer.putShort((short) buf.length);
-            buffer.put(buf);
+            return;
+        }
+        byte[] buf = str.getBytes(StandardCharsets.UTF_8);
+        if (buf.length > 1024) {
+            LOGGER.warn("Attempting to write string longer than 1024 bytes: '{}'. Please raise an issue.", str);
+            str = str.substring(0, 1033);
+            while (buf.length > 1024) {
+                str = str.substring(0, str.length() - 12) + "…";
+                buf = str.getBytes(StandardCharsets.UTF_8);
+            }
         }
+        buffer.putShort((short) buf.length);
+        buffer.put(buf);
+    }
+
+    protected ByteBuffer buffer() {
+        return buffer;
     }
 
     public String toString() {

common/src/test/java/org/mvndaemon/mvnd/common/DaemonRegistryTest.java

@@ -17,6 +17,8 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.Locale;
@@ -50,7 +52,53 @@ public void testReadWrite() throws IOException {
             assertNotNull(reg2.getAll());
             assertEquals(1, reg2.getAll().size());
         }
+    }
 
+    @Test
+    public void testRecovery() throws IOException {
+        Path temp = File.createTempFile("reg", ".data").toPath();
+        temp.toFile().deleteOnExit();
+        try (TestDaemonRegistry reg1 = new TestDaemonRegistry(temp)) {
+            // first store daemon
+            byte[] token = new byte[16];
+            new Random().nextBytes(token);
+            reg1.store(new DaemonInfo("12345678", "/java/home/",
+                    "/data/reg/", 0x12345678, 7502, token,
+                    Locale.getDefault().toLanguageTag(), Arrays.asList("-Xmx"),
+                    DaemonState.Idle, System.currentTimeMillis(), System.currentTimeMillis()));
+            assertEquals(1, reg1.getAll().size());
+            // store an invalid event to trigger recovery
+            StringBuilder sb = new StringBuilder(1024);
+            for (int i = 0; i < 1024; i++) {
+                sb.append('…');
+            }
+            reg1.storeStopEvent(new DaemonStopEvent("11111",
+                    System.currentTimeMillis(),
+                    DaemonExpirationStatus.QUIET_EXPIRE,
+                    sb.toString()));
+            assertEquals(1, reg1.doGetDaemonStopEvents().size());
+            // check if registry is reset
+            assertEquals(0, reg1.getAll().size());
+            assertEquals(0, reg1.doGetDaemonStopEvents().size());
+        }
+    }
+
+    static class TestDaemonRegistry extends DaemonRegistry {
+        public TestDaemonRegistry(Path registryFile) {
+            super(registryFile);
+        }
+
+        @Override
+        protected void writeString(String str) {
+            ByteBuffer buffer = buffer();
+            if (str == null) {
+                buffer.putShort((short) -1);
+            } else {
+                byte[] buf = str.getBytes(StandardCharsets.UTF_8);
+                buffer.putShort((short) buf.length);
+                buffer.put(buf);
+            }
+        }
     }
 
 }